Upgrading an information technology (IT) system often requires backward compatibility. For example, a system originally implemented with a 1 Mbit/sec serial interface may be upgraded to include an interface of 1 Gbit/sec. In some circumstances, the system may be required to transmit the lower and higher speed transmissions over the same physical medium. However, the low speed and high speed interfaces may be incompatible with each other. In certain circumstances, such lower speed signals could possibly damage the high speed interfaces.